The present invention relates generally to surgical instruments, and more particularly to devices and methods for stabilizing and manipulating tissue during surgery. The tissue stabilizers described herein are particularly useful for stabilizing the beating heart during coronary artery bypass graft surgery. The field of the invention is cardiac tissue stabilizers having specially designed moveable portions.
Certain surgical procedures require the surgeon to perform delicate operations on tissues within the body that are moving or otherwise unstable. For example, a large and growing number of surgeons are routinely performing successful coronary artery bypass graft surgery on the beating heart. In a typical coronary artery bypass graft (CABG) procedure, a blocked or restricted section of coronary artery, which normally supplies blood to a portion of the heart, is bypassed using a source vessel or a graft vessel to re-establish blood flow to the artery downstream of the blockage. This procedure requires the surgeon to create a fluid connection, or anastomosis, between the source or graft vessel and an arteriotomy or incision in the coronary artery. Forming an anastomosis between two vessels in this manner is a particularly delicate procedure requiring the precise placement of tiny sutures in the tissue surrounding the arteriotomy in the coronary artery and in the source or graft vessel so that the two may be sutured together.
To ensure that the sutures may be placed with the required accuracy and precision to yield an anastomosis having long term patency, a number of devices have been developed to stabilize a portion of the heart in the vicinity of the target coronary artery. The vast majority of devices suitable for successfully stabilizing the beating heart use either compression or vacuum, or both, to engage and immobilize a portion of cardiac tissue, preferably along opposite sides of the target artery. Devices configured to use a compressive force to stabilize a surgical site on the beating heart can be found, for example, in U.S. Pat. No. 5,894,843 to Benetti et al. Examples of devices configured to use negative pressure or vacuum to stabilize or to assist in stabilizing cardiac tissue are described, for example, in U.S. Pat. No. 5,727,569 to Benetti et al. and U.S. Pat. No. 5,836,311 to Borst et al.
Although some stabilization devices reduce or eliminate the motion of the heart at the surgical site or target artery, visualization or presentation of the target artery, and more specifically the arteriotomy to which a vessel will be anastomosed, could be improved in certain surgeries. While a properly stabilized vessel will usually exhibit acceptable visualization, some operations and tissue geometries can distort the tissue surrounding the coronary artery or the coronary artery itself in a manner which complicates the completion of the anastomosis. For instance, excessive pushing on the cardiac tissue along each side of the coronary artery may tend to flatten the target artery top to bottom while pulling may tend to compress the target artery side to side as tissue is pulled higher than the target artery. In other instances, the target coronary artery is not conveniently located along the surface of the myocardium, but instead is partly or completely covered by fat or other tissue. In such cases, the stabilization forces alone can do little to optimize the visualization and presentation of the target artery.
The presentation of the target vessel and the arteriotomy is a significant factor in eliminating anastomotic errors which may cause vessel damage or a less than optimal anastomosis which may lead to failure of the anastomosis. When the arteriotomy is not optimally presented, there is a higher likelihood of incurring a surgical error in the formation of the anastomosis. To suture an anastomosis the surgeon generally works his needle from the inside vessel wall to the outside of the vessel wall. If the vessel is flattened, for example, it becomes more likely for the surgeon to accidentally catch the back wall of the vessel with the curved suture needle as the suture is placed in the tissue surrounding the arteriotomy. When the vessel is compressed side to side, it becomes more difficult to catch only the desired side of the arteriotomy without also catching the other side.
When the edges of the arteriotomy are not presented as desired, the surgeon may be required to manually manipulate the target artery using forceps or the like. The surgeon must be careful to only manipulate the vessel at the outside edges of the incision as manipulation to the interior of the vessel wall may cause damage to the soft intimal layer of the vessel leading to scarring and often late restenosis. Most often, the surgeon will try to only manipulate the tunica adventitia or outer coat of the vessel using forceps or other suitable instrument to present the arteriotomy in a manner which allows an accurate placement of each suture in the vessel from the inside out.
Even in the best of circumstances this manual manipulation of the vessel to facilitate each suture placement is tedious, time consuming, and increases the likelihood of vessel damage. This problem will become even more magnified as surgeons move to manual, computer-assisted, and robotic endoscopic procedures in which the surgeons will be attempting to complete anastomotic procedures in remote and difficult places. Delicate manipulation of the vessel walls while suturing becomes increasingly difficult as the surgeon becomes further removed from the surgical site by longer instruments, the size of the surgical site decreases leaving inadequate space to accommodate multiple instruments, and the access incisions become smaller thus limiting instrument maneuverability.
In view of the foregoing, it would be desirable to have methods and devices which provide stabilization of the surgical site and target coronary artery and also provide favorable presentation of the edges of the arteriotomy so that manual manipulation of the vessel itself is reduced or eliminated. It would further be desirable to have stabilization and presentation devices which are adaptable to anatomical variations to aid in exposure of intramyocardial vessels and provide optimal vessel presentation over a wide range of operating conditions.
The present invention will be described for use during CABG surgery, but the invention is not limited thereto, and is contemplated to be useful for other surgical procedures as well.
The present invention involves a tissue stabilizer having one or more stabilizer feet which are adapted to engage the heart tissue adjacent a target artery desired to be stabilized. In preferred embodiments of the present invention, the tissue stabilizer feet typically have a first foot portion which provides stabilization and a moveable portion which primarily facilitates the manipulation of the target coronary artery or local tissue surrounding the target coronary artery.
One aspect of the present invention involves a tissue stabilizer having at least one stabilizer foot having a first portion and a second portion coupled to the first portion. The first portion is preferably substantially rigid having a tissue engaging surface adapted to engage a first area on the surface of the tissue to be stabilized. The second portion may have a vacuum chamber with at least one opening adapted to engage a second area on the surface of the tissue. Preferably, the second portion is moveable relative to the first portion whereby movement of the second portion relative to the first portion manipulates the second area of tissue relative to the first area of tissue. In a preferred embodiment, the second portion, or at least a portion of the second portion, flexes, pivots, or otherwise moves upwardly relative to the first portion.
By way of example only, the tissue engaging surface may comprise a textured surface adapted to frictionally engage the first area on the surface of the tissue or may include a vacuum chamber and at least one opening in fluid communication with the vacuum chamber. When the tissue engaging surface involves a vacuum chamber, a raised seal may be disposed completely around the perimeter of the tissue engaging surface. Preferably, the raised seal is compressible so that it may conform somewhat to the surface of the tissue, but may be relatively rigid to more aggressively contact the tissue surface to form a seal.
The device may include a tension member having a distal end connected to the second foot portion. The tension member may be pulled or otherwise operated to cause the desired movement of the second portion. The tension member may be a thread material, a flexible wire, a cable, a braid, or other linkage by which the second portion can be manipulated.
The proximal end of the tension member may be connected to a tensioning mechanism. In one variation, the tensioning mechanism may include a channel adapted to receive the tension member and a locking member positioned at an angle relative to the channel and having a free end biased against the interior of said channel to trap and secure a portion of the tension member between the channel and the free end. In another variation, the tensioning mechanism may comprise a pivoting member having a pivot axis. The proximal end of the tension member may be attached to the pivoting member at a predetermined distance from the pivot axis. The tension member may also involve a spool having an outer surface about which the proximal end of the tension member may be operably connected.
In preferred embodiment, the second portion is made of a flexible material. Suitable material for the second portion may include silicone, urethane rubber, nitrite rubber, hytrel, kraton, or other medical grade flexible materials. Most preferably, the second portion comprises an elastomer.
In one preferred embodiment, the tissue stabilizer has a first stabilizer foot and a second stabilizer foot substantially parallel to the first stabilizer foot, each of the first and second stabilizer feet having a first portion and a second portion coupled to the first portion. The first portion is preferably substantially rigid and has a tissue engaging surface adapted to engage a first area on the surface of the tissue. The second portion preferably has a vacuum chamber with at least one opening adapted to engage a second area on the surface of the tissue and is moveable relative to the first portion whereby movement of the second portion relative to the first portion manipulates the second area of tissue relative to the first area of tissue. Preferably, the second portion is adapted to lift or roll up the second area of tissue relative to the first area of tissue stabilized by the first foot portions of the stabilizer feet.
Another aspect of the present invention involves a device for stabilizing tissue within a patient""s body comprising at least one stabilizer foot having a first foot portion adapted to engage a first portion of tissue and a second foot portion having a vacuum space having at least one opening adapted to engage a second portion of tissue immediately adjacent the first portion of tissue, the second foot portion being flexibly coupled to the first foot portion. The tissue stabilizer may further include a tension member having its distal end operably attached to the second foot portion whereby pulling on the proximal end of the tension member causes the second foot portion to move relative to the first foot portion.
To engage the first portion of tissue, the first foot portion preferably has a vacuum chamber having at least one opening adapted to engage the first portion of tissue with negative pressure or a textured surface adapted to frictionally engage the portion of tissue. The textured surface may include a large number of small protrusions which are preferably formed by chemical machining or etching or other suitable process. To engage the second portion of tissue, the second foot portion preferably defines a vacuum space having a perimeter edge adapted to seal against the second portion tissue. Preferably, the second foot portion comprises an elastomeric material.
Another aspect of the present invention involves a device for stabilizing tissue within a patient""s body for performing a surgical procedure on the tissue comprising a base member having an interior chamber and a substantially cylindrical bore and a stabilizer foot having a mating fitting positioned within said bore and being rotatable within said bore. The bore preferably has a first end in fluid communication with the interior chamber and a second end open to the exterior of the base member. The fitting is preferably substantially cylindrical having a longitudinal axis about which the fitting rotates within the bore. The stabilizer foot may have a first foot portion adapted to engage a first portion of tissue and a second foot portion adapted to engage a second portion of tissue adjacent the first portion of tissue, the second foot portion being flexibly coupled to the first foot portion.
The second portion is preferably made of an elastomer and defines a vacuum space or chamber having at least one opening in fluid communication with the second portion of tissue. Preferably, the vacuum space has a perimeter edge adapted to seal against the second portion of tissue.
Another aspect of the present invention involves a device for stabilizing tissue within a patient""s body for performing a surgical procedure on the tissue comprising a first stabilizer foot having a first tissue engaging surface, a second stabilizer foot having a second tissue engaging surface, and base member having a shaft mounted for rotation relative to the base member. The shaft preferably has at least one threaded portion. The first and second tissue engaging surfaces may extend generally perpendicular to the longitudinal axis of the shaft. At least one of the stabilizer feet may be operably associated with the threaded portion of the shaft such that rotation of the shaft causes one of the stabilizer feet to move relative to the other.
In a preferred embodiment, the shaft has a first threaded portion and a second threaded portion and the first stabilizer foot is adapted to receive and traverse along the first threaded portion and the second stabilizer foot is adapted to receive and traverse along the second threaded portion. Preferably, the second threaded portion has threads which are opposite-handed to that of the threads of the first portion. With that configuration, rotation of the shaft in a first direction moves the stabilizer feet closer together while rotation in the opposite direction moves the feet further apart.
One or both of the stabilizer feet may further include a flexible member moveably coupled thereto, the flexible member having a vacuum chamber having at least one opening for engaging a portion of tissue with negative pressure. In a preferred embodiment, the flexible member comprises an elastomer.
Another aspect of the present invention involves a method of stabilizing a coronary artery on a beating heart for performing a surgical procedure on the coronary artery. The method preferably involves the steps of providing a tissue stabilizer having at least one stabilizer foot having a first portion adapted to engage a first area on the surface of the heart adjacent the coronary artery a second portion adapted to engage a second area on the surface of the heart, engaging the first area with the first portion to substantially stabilize at least a portion of the heart, engaging the second area with the second portion, and moving the second portion relative to the first portion whereby the second area of the heart is moved relative to the first area of the heart. Preferably, the second area includes at least a portion of the coronary artery.
The method may also include the step of forming an incision or arteriotomy having a first side and a second side in the coronary artery after engaging the first area with the first portion. The second area preferably includes a portion of the coronary artery adjacent to the first side of the arteriotomy whereby the step of moving the second portion relative to the first portion moves the first side of the arteriotomy relative to the second side of the arteriotomy. Once the desired side of the arteriotomy has been positioned or oriented as desired, one or more sutures may be placed through the arteriotomy or the tissue immediately adjacent the incision.
In a preferred embodiment, the tissue stabilizer has first and second stabilizer feet, each having a first portion and a second portion coupled to said first portion and moveable relative to said first portion. The method preferably includes the step of adjusting one or both of the stabilizer feet relative to each other to ensure a good fit against the surface of the heart. The first portion of each stabilizer foot may then be engaged with the surface of the heart on opposite sides of the coronary artery. An arteriotomy having a first side and a second side may be created in the coronary artery. In the preferred method, the first side is positioned relative to the second side by engaging one or both of the second portions of the stabilizer feet with the heart and moving one or both relative to the first portions. The method may also include the step of manipulating the first and second stabilizer feet relative to one another to improve presentation of the arteriotomy.
These and other features of the present invention will become more fully apparent from the following description and appended claims.